Manufacture of zinc oxid.



A. BLUM.

MANUFACTURE OF ZINC OXID. APPLIQATION FILED now. 17, 1910.

993,019, Patented May 23,1911.

WITNESSES: INVENTOR' ad'k I ATTORNEYS E ABRAHAM LBIQUM, F MONTEREY, MEXICO.

MANUFACTURE OF ZINC OXID.

Specification of Letters Patent. Patented lflny 23, 1911.

Application filed q ctober 17; 1910. Serial No. 587,615.

To all whom it may concern: low pressure or the blast prohibits the use Be it known that I, Anmrusr Rent. a of more than one layer of charge above the citizen of the Republic of France, residing burning coal, because the slag incident to the at and whose post-oflice address is Montercy, operation so far reduces the pressure of the Nuevo Leon, Republic of Mexico, have iublast that the reduction of zinc ore in a 60 vented certain new and useful Improvements second layer would not be possible. In the in the Manufacture of Zinc Oxid; and I do \Vetherill process, therefore, as above noted, hereby declare the following to be a full, only a single layer of the zinc ore charge is clear, and exact description of the invention, treated, and it is necessary to clean the fur- 10. such as will enable others skilled in the art nace grate at the termination of the opera- 6% to which it appertains to make and use the tion and before the furnace ,is recharged.\ same. Consequently, the etherill furnace, al-

My invention has for its object the producthough realizing a good recovery, is corretion, directly from crude zinc ore of high spondingly expensive, because of the relaor low grade, calcined zinc ore, or like zinkiftively small amount of ore which a single 70 crous material, of a high grade white oxid, furnace can treat per day. carrying, in most instances, as high as 75 Experiments have also been made for the to 80% of zinc. treatment of the residues of zinc smelter-s,

, The fundamental orcharacteristic feature by mixin said residueswith 40% of coal of the invention consists in making 'up the and blowing the mixture, under high pres- 75 charge to he treated, of a plurality of layers. sure, in a converter of the Huntington and of fuel, alternating with a plurality of layers l-leberlein type. These experiments, howof mixed fuel and zinc ore. The layers of ever, have not, insofar as I am aware, re

' fuel referred to constitute auxiliary heating sulted in a commercial process.- The depth zones intermediate of the layers of mixed of-the charge employed necessitates the can-3 fuel and ore. The layers of mixed fuel and ployment of a blast of high pressure in orore constitute zones wherein the zinc ore 'der that the zinc may be extracted before the, is subjected by direct contact to the reducing slag is formed. Furthermore, it is necessary action of the fuel forming a part of the mix-. to heat up the charge very quickly, otherture. The resultant effect is that the desired wise the zinc'oxid produced, coming in con- 6- conditions for effectively reducing the ore tact with the cold upper part of the charge, and for oxidizing the zinc vapors produced will remain therein in a crystallized condito white oxid, are fully realized, while, at the tion and will not be volatilized again, so saine time, the total amount of zinc ore that the recovery is correspondingly poor.

capable of being treated in a single charge Moreover, the employment of a blast of high is correspondingly multiplied. pressure produces furnace conditions whi h In the \Vetheri-H process for the producresult in the reduction of the iron oxid con tion of white zinc oxid from the ore, ore tained in the ore. The iron is-thereupon remixed with coal is thrown upon a bed of oxidized and passes with the zinc oxid into 0'burning coal spread out upon a. special perthe filter bags, making the zinc oxid. yellow. forated grate, through which air is'blown. and the zinc oxid itself is found to carry not The products of combustion, together with more than 60? of zinc. in contradistiuction the zinc oxid, are drawn off from thefurnace to the much higher percentage of zinc carand the zinc oxid is filtered out in the bag ried by white oxid. Finally, because of the 45 room provided for the purpose. The capachigh temperature incident to the operation, ity' of the ether-ill furnace varies from it. is difficult to treat a charge containing about 120 to 150 kilos, and the furnaces are I more than 400 kilos of ore. In the practice generally as embled in double groups of six. of my invention, on the contrary, it eu- It takes f om six to eight hours to burn a tirely feasible to treat charges containing 50 single charge; the furnace burns three frome one to three tons of ore at a single opcharges a day and requires the same weight oration, and in an ordinary conical pot or of coal and ore and needs three men per converter, having aperforated bottom. The group. The Wetherill furnace is of the realternate arrangement of the layers of coal, verberatory type and is operated with a blast and of oreand coal mixed, as employed by 55 offrom one to two ounces pressure. The me,permits the desired temperature conditions' to be realized promptly throughout the charge, so that the reduction proceeds with corresponding uniformity. Crystallization of zinc. oxid in the upper layers of the charge is avoided, and the pressure of the blast is restricted to such a range that the zinc oxid produced is not yellowed by the reductlon of the iron oxid constituent ofthe ore andporous cinder is produced which may be readily discharged from the converting ve s-. sel and which, during its format-ion, does not interfere with the conduct or progress of the operation.

- In carrying out my invention, I may emloy any suitable pot or converter, as, for;

instance, the well known Huntington and Heberlein converter. However, I have found particularly serviceable for the purpose an ordinary conical pot having a perforated false bottom. For instance, a converter actually-used by me was of the conical type, one

meter high and 1.20 meters in diameter at its upper edge. The opening for the entrance of the air blast, in the converter referred. to,-was 20 cm. and was below the false bottom, which, slightly curved or arched, had a diameter of 80 cm. with a series' of perforationsextending through it of about 11 mm. in diameter.

The pot or converter was capped with an iron hood and I connected with the bag house through a pipe line cm. in diameter and 30 meters long.' The bag house was connected with the pipe line through a fan and was provided with a settling chamber and the necessary cotton cloth filter bags. In using a pot or converter of this general character, I have found it suitable and desirable to employ layers of a thickness of 10 cm. in making up the charge, these layers-being alternately anthracite coal and a mixture of anthracite coal and zinc ore. Forinstance,

for the'treatment of a zinc ore made up of fines, running Minas Viejas crude low grade and free from 23% of zinc and 23% of iron,

lead and arsenic, I have employed a coal having volatile matter 7%; fixed carbon 86.8%, and ash 6.2%. In this particular instance, when a four-layer charge was employed, (2'. e., a bottom layer of coal resting upon the perforated grate, a layer of mixed zinc ore and coal resting upon the bottom layer, a layer of coal resting .upon the mixed ore and coal layer, and a top layer of mixed ore and coal) the [entire charge contained 120 kilos of ore and 120 kilos of coal. 4:8

kilosvof the coal was used in making up the layers of mixed ore and coal and may properly be designated as reducing coal. The remainin 72 kilos were used for the auxiliary heatmg layers and may be designated as .heating coal. The ore was crushed to 6 mm., the reducing coal to 12 mm., and the heating coal to 25 mm. Each layer was of a thickness of 10 cm. Theignited charge was then blasted, beginning at a pressure of two inches, gradually rising to twelve inches as the operation progressed, and being-again lowered somewhat. A good reaction was started after thirty minutes and the blast was-continued for a period of six hours, the resulting product being a zinc oxid containing 76.5% of zinc. While good results can be thus obtained from the employment of four layers ,as described, I nevertheless prefer and recommend the employment of an additional layer of cgtal and an additional layer of mixedv ore nd coal, making six alternate layers of the same preferred thickness of 10 cm. In such case it will usually be preferable to conti he the blow up to say seven hours, because if the greater amount of ma terial treated and because the react-ion does not seem to start as promptly. In general, it will not be found advisable to materially exceed this proposed maximum, for the reason that to do so would increase the duration of treatment of the charge and consequently there would be no saving in the capacity of the converter.

It will, of course, be understood that the 9.5 example that I have above given from actual practice is but one illustration of the capacity and character of the invention. 7 Even with the Minas Viej as low grade crude fines the process gave a product of'good quality, although the crude ore contained as low as 23% of zinc and as high as 23% of iron, and although the converter employed was of a relatively moderate capacity.' For,

larger industrial uses I recommend a pot or converter, say 75 cm. high and 2.10 meters inside diameter, which would be able to treat, under similar conditions of operation, three tons of ore in a single charge, or nine tons per day, an amount equal to thedaily capacity of twenty VVetherill furnaces. So also, two converters, each having a capacity for treating nine tons'of" ore, '5. a, a total capacity of eighteen tons, will require for their operation not more than five men, a saving of 50% of labor for equal capacity,

as compared with the Wetherill furnace, twelve VVetherill furnaces requiring the .cslervices of three mento 5.4 tons of ore per In the accompanying drawing, I have illustrated a suitable apparatus for the practice of my invention. The pot" A, which may be supported in any convenient way, as, for instance, on the;wheeled truck B, is provided with an air-blast pipe, (1, and a perforated bottom 6; Upon the perforated bottom are arranged the layers of heating coal 0', alternating'with the layers of mixed ore and reducing coal 2.

0 represents a collecting hood, having a pipe line d leading to the bag room, and a ipe f leading to the chimney, these pipes eing severally provided with valves or dampers, for the purposes hereinbefore described. The hood may further be provided with a suitable number of closable charging lesser thickness; but, in general, it will not be advisable to increase the thickness of any of the layers to exceed 20 cm. nor to have any of them of materially lesser thickness than 10 cm. In all cases, having in view the composition of the'particular grade of ore treated, provision must be made to obtain the thermal effects desired in the heating zones or layers, and the corresponding reducing effects in the layers of mixed coal and ore, by making appropriate distribution of the coal employed; that is to say, by using coal layers of thickness sufiicient to meet the requirements of the layers of mixed ore and coal, and by using an amount of reduclng coal in the mixed layers suitable to the kind of ore under treatment. If lead is a constituent of the ore, the product will be a white zinc-lead pigment.

Beforethe starting up of the reaction the products of combustion, which always contain some free hydrocarbon, should be discharged through the furnace stack, without going to the bag room; otherwise there-will result more or less yellowing of the zinc white oxid. But should the connection to the bag be made prematurely, any resultant yellowing of the product can be removed by subjecting it to heat in a muifie for a few minutes.

Having now described my invention, what I claim is:

1. The method of making zinc oxid from zinkiferous material, such-as calcined zinc ore, crude zinc ore, and the like, ,which consists in establishing a charge made up of a plurality of layers of zinkiferous material mixed with crushed fuel for reduction, alternating with a plurality of layers of crushed fuel constituting auxiliary heating zones therefor, blasting the charge with air, and recovering the resultant zinc oxid fumes; substantially as described.

2. The method of making zinc oxid from zinkiferous material, such as calcined zinc ore, crude zinc ore, and the like, which con-- sists in establishing a charge made up of a plurality of layers of the zinkiferous ma- ,terial mixed with fuel for reduction, alternating with a plurality of layers of fuel constituting auxiliary heating zones therefor, blasting the charge with air admitted during the earlier stage of the operation at relatively low pressure, subsequently at higher pressure, and finally at lower pressure, and recovering the resultant zinc oxid fumes; substantially as described.

3. The method of making zinc oxid from zinkiferous material, such as calcined zinc ore, crude zinc ore, and the like, which consists-in establishing a charge made up of a plurality of layers of the zinkiferous material mixed with fuel for reduction, alternating with a plurality of layers of fuel constituting auxiliary'heating zones therefor, air-blasting the charge at a temperature lower than the reducing point of any iron oxid present,-and recovering the resultant zinc oxid fumes; substantially as described.

4. The method of making zinc oxid from zinkiferous material, such as calcined zinc ore, crude zinc ore, and the like, which consists in establishing a charge made up of a pluralityof layers of the zinkiferous material mixed with fuel for reduction, alternating with a plurality of layers of fuel con stituting auxiliary heating zones therefor; air-blasting the charge at a temperature to produce a cinder in contradistinetion to a slag, and IQCOVGIlIlf the resultant zinc oxid fumes; substantiallg as described.

5. The method of making zinc oxid from zinkiferous material, such as calcined zinc ore, crude zinc ore, and the like, which consists in establishing a charge made up of a plurality of layers of the zinkiferous material mixed with fuel for reduction, alternating with a lurality of layers of fuel constituting auxi iary heating zones therefor, air-blastingrthe charge at a pressure whose maximum does not materially exceed twelve ounces, and recovering the resultant zinc oxid fumes; substantially as described.

6. The method of making zinc oxid from zinkiferous material, such as calcir l zinc ore, crude zinc ore, and the like, wh; -.h consists in establishing a charge made up of a plurality of layers of the zinkiferous material mixed with crushed fuel for reduction,

alternating with a plurality of layers of crushed fuel constituting auxiliary heating zones therefor, the total amount of fuel present being approximately from forty to fifty per cent. by weighg of the charge, airblasting the char e, an recovering the resultant zinc oxid umes; substantially as described.

7. The method of making zine oxid from zinkiferous material, such as calcined zinc ore, crude zinc ore, and the like. which consists in establishing a charge made up of a plurality of layers of the zinkifei'oue material mixed with crushed fuel for reduction, alternating with a plurality oflayers of crushed fuel constituting auxiliary heating zones therefonthe amount of fuel pres-- ent in the layers of mixed fuel and ore being less than that present in the other layers, airblasting the charge, and recovering the resultant'zinc oxid fumes; substantially as described.

terial, air-blasting the charge, and recovering the'resultant zinc 'oxid fumes; substantially as described. 7 9. The method of inaking zinc oxid from 'zinkiferous material, 'such as calcined zinc ore, crude zinc ore, and the like, which consists in establishing a charge made up of a plurality of layers of the zinkiferous material mixed With fuel for reduction, alternating with a plurality of layers of fuel constituting auxiliary heating zones therefor, the maximum number of layers being six and the layer thickness approximately ten centimeters; substantially as described.

In testimony whereof I affix my signature,

in presence of two witnesses.

J ABRAHAM BL'UM. VVit-nesses:

E. M. VILLAREAu,

J. C. ALLEN.

Oopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, I). G. 

